At 2-3 months post-stroke and again at 10-12 months patients will be studied using the technical expertise and infrastructure of Core B in three ways: 1) neuropsychological testing to document recovery of language, sensorimotor, and spatial attention performance;2) structural MRIs that will be analyzed volumetrically to assess lesion parameters and possible changes during the period of recovery;and 3) MEG testing, where the activation profiles specific to language, motor, somatosensory, and spatial attention functions will be obtained. In addition to volumetric analysis, the structural MRIs will be used for co-registering MEG data. Some of the patients, specifically a subset of those from Memorial Hermann Hospital (MHH), will have undergone constraint-induced therapy (CIT) for motor function, which will be completed by 2 months post-stroke, in the context of an ongoing study conducted by Dr. James Grotta. The effects of CIT on reorganization of the brain mechanisms of sensorimotor behavior will be assessed by comparing data of patients who have undergone therapy and patients who have not (Projects 2 and 3). Each of the two MEG/MRI imaging/neuropsychological testing sessions (at 2-3 and 10-12 months) that will take place using the infrastructure of Core B will be performed over the course of two days. On the first day patients will receive neuropsychological testing and MEG imaging. On the second day they will receive MRI imaging. MEG imaging will take approximately 1? hours, including preparation, for a single project. If patients are enrolled in an additional project (they will be limited to 2 of the 3 projects), additional MEG imaging time will be approximately 45 minutes, occurring immediately following the MEG scan for the first project, within the context of the same imaging session. Neuropsychological testing will be at most 1 hour for 2 projects. Therefore, even if patients are enrolled in two projects they should, with rest and lunch breaks, be able to complete MEG imaging and neuropsychological testing in one day. MRI images obtained on the second day will be the same for all studies. Figure 1 of the Introduction to the Program Project (page 110) is a flow chart illustrating the successive stages of the Program Project. All three sets of data (neuropsychological, volumetric MRI, and MEG) generated in the context of Core B will be integrated and checked in Core A and then they will be made available to the PIs of Projects 1, 2, and 3, who are also Co-Investigators in Core B. Each project PI, will use the subset of data that is required for testing his or her specific hypotheses. As described in more detail below, Project 1 will utilize brain activation profiles specific to language;Project 2 will use activation profiles specific to motor behavior;and Project 3 will use activation profiles specific to somatic sensation and spatial attention. Activation profiles corresponding to each function will be also studied in the context of Core B, to document any possible repercussions of reorganization of the mechanisms that mediate the functions affected by the stroke, to mechanisms of functions unaffected by the stroke.